Response of the Ionospheric Convection Pattern to a Rotation of the Interplanetary Magnetic Field on January 14, 1988

• Ionospheric convection signatures observed over the polar regions are provided by the DMSP F8 satellite. We consider five passes over the southern summer hemisphere during a time when the z component of the interplanetary magnetic field was stable and positive and the y component changed slowly from positive to negative. Large-scale regions of sunward flow are observed at very high latitudes consistent with a strong z component. When B(y) and B(z) are positive, but B(y) is greater than B(z), strong evidence exists for dayside merging in a manner similar to that expected when B(z) is negative. This signature is diminished as B(y) decreases and becomes smaller than B(z) resulting in a four-cell convection pattern displaced toward the sunward side of the dawn-dusk meridian. In this case the sign of B(y) affects the relative sizes of the two highest-latitude cells. In the southern hemisphere the dusk side high-latitude cell is dominant for B(y) positive and the dawnside high-latitude cell is dominant for B(y) negative. The relative importance of possible electric field sources in the low-latitude boundary layer, the dayside cusp, and the lobe all need to be considered to adequately explain the observed evolution of the convection pattern.

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NATURVETENSKAP  -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)

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